JPH11137908A - Deaerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum deaerator by which almost continuous water passing deaeration can be performed by a synergistic effect of low temperature boiling in a vacuum vessel and cavitation by ultrasonic waves, being not dependent on environmental conditions such as seasonal changes, and the removal of dissolved gas can be attained without chemical infection or heating. SOLUTION: This deaerator has a water introducing cylinder 15 for giving vacuum low temperature boiling and cavitation to water with which it is filled, ultrasonic vibrator transducers for radiating ultrasonic waves for causing cavitation to the water within the water introducing cylinder 15, a deaeration chamber 7 evacuated by a vacuum pump 17, a centrifugal pump 3 for sending the water in the water introducing cylinder 15 to the deaeration chamber 7, and a water sending means for water stored in the deaeration chamber 7 to the outside. The centrifugal pump 3 sucks water from an area adjacent to the axial center of the upper end of the water introducing cylinder 15 while generating a rising rotational vortex of the axial center along about the axial direction of the water introducing cylinder to the water within the water introducing cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator for removing dissolved gas from tap water, intermediate water or sewage, and more particularly to a deaerator which can be used in continuous processing and can be made compact.

[0002]

2. Description of the Related Art It is well known that water is passed through an ion-exchange resin cylinder to reduce carbonate hardness and soften water, for example, in a boiler water supply system. In this case, if the oxide is dissolved in the water introduced into the ion exchange resin cylinder, irreversible swelling due to oxidation occurs in the case of a strong acid / weakly acidic cation exchange resin, and exchange occurs by oxidation in the case of an anion exchange resin. Since the group is decomposed or irreversible swelling, it may cause a serious problem that affects the durability of the ion exchange resin unless the oxide is dissolved or mixed in the water when passing water. . For example, when iron ions and copper ions eluted from the flaws in the lining of the piping are mixed as rust due to the reaction with dissolved oxygen in water, the ion exchange resin is oxidized and deteriorated by their catalytic action. .

[0003] Therefore, conventionally, when dissolution or mixing of oxides is found in water flow, or when it is likely to occur, descaling and corrosion of water are performed before water flow through the ion exchange resin. It is common sense to perform pretreatment for the purpose of prevention or the like.

[0004] The most common pretreatment of this type is a chemical injection method in which a chemical compounding a deoxidizing agent such as hydrazine, which is highly toxic for removing dissolved oxygen, and a cleaning agent for increasing pH is added to water. It is.

[0005] As a method which does not rely on chemical injection, a vacuum degassing method in which oxygen, carbon dioxide, free chlorine, and the like dissolved in water are degassed in a container having a high vacuum degree is also known. In addition, a multistage continuous vacuum degassing system combining an ejector and a cyclone for mass processing is also known.

In addition, for example, Japanese Patent Publication No. 2-11
No. 319, No. 2-1640 or No. 6
Japanese Patent No. 38959 teaches that when a mineral component in water is ion-dissociated in a tank for applying an electrostatic field or an oscillating electric field to precipitate and remove as a floating scale, the inside of the tank is depressurized and degassed.

[0007]

The chemical injection method is not suitable for use in hospitals and food factories because of the toxicity of the deoxidizing agent. Of course, when the chemical injection is performed upstream of the ion exchange resin cylinder,
The amount of impurities in water increases by that amount, which not only increases the load on the ion exchange resin, but also tends to naturally increase the amount of chemical injection, making it difficult to monitor the appropriate amount of chemicals in management. However, it is not common except for uses in strictly controlled factories and the like where added value is expected for the use of chemicals because of problems such as the accompanying use and increase in the amount of chemicals used.

[0008] The vacuum degassing method is a method that does not pose a problem from a sanitary point of view, but has a difficulty in controlling the degree of vacuum as a treatment of domestic water supply or a measure against red water in a building or the like. Since the atmospheric pressure and the water temperature or the temperature greatly change depending on the season, it is not possible to maintain a constant deaeration performance only by adjusting the vacuum pressure. For this reason, the vacuum deaeration system has not yet become widespread, but a batch processing type vacuum deaerator can be relatively easily handled. However, the batch processing type vacuum deaerator has a limited amount of processing because the processing is discontinuous, and when a large amount of water needs to be processed, it must be a large-scale equipment, and equipment maintenance cost is required. It is not common because it is expensive.

On the other hand, when continuous large-volume treatment is required as in a food factory, for example, a multi-stage continuous vacuum degassing system combining an ejector and a cyclone that requires specialized and complicated operation and maintenance is required. Equipment that has been adopted and has a sufficient amount of processing per hour has been put to practical use.However, since the installation area is large, the equipment cost and maintenance cost are large, it is suitable for industrial use where added value can be expected by processing, and it is suitable for general apartments. As a deaerator for water treatment facilities in offices and office buildings, etc., it is not practical to adopt it economically, including in terms of management.

It is also known to carry out a hollow fiber membrane deaeration method upstream of an ion exchange resin cylinder. In this case, metal ions in water are oxidized on the surface of the hollow fiber membrane, and this oxide is removed. As a result, the membrane adheres to the membrane and malfunctions due to obstruction of the deaeration passage, and frequent replacement of the membrane is required. As a result, running costs are high except for high value-added applications, and there is a drawback that it cannot be economically justified.

The use of a hollow fiber membrane downstream of an ion exchange resin is also effective for simply removing dissolved oxygen.
In this case as well, for example, in a boiler facility, metal ion components dissolved from a steam return pipe or a circulating hot water pipe are oxidized and adhere to and solidify on the hollow fiber membrane surface, causing clogging. The disadvantages that must be taken early are inevitable.

By heating and boiling the treated water in combination with the vacuum degassing treatment, a carcinogenic substance such as trihalomethane or trichlorethylene in the water or O-15 is produced.
It is also known that harmful bacteria such as 7 can be removed at the same time. However, even if boiling in a hot water supply system is possible, in a water supply system that supplies cold water, considering the energy consumption of boiling and cooling, it is realistic. poor.

Accordingly, an object of the present invention is to enable substantially continuous deaeration of water through synergy between low-temperature boiling in a decompression vessel and cavitation by ultrasonic waves without being affected by environmental conditions such as seasonal changes. It is to provide a new vacuum deaerator.

Another object of the present invention is to provide a deaerator which can eliminate dissolved gas without the need for chemical injection or without heating.

[0015]

In order to solve the above-mentioned problems, a deaerator according to the present invention is provided with a water-guiding cylinder for applying reduced-pressure low-temperature boiling and cavitation to water introduced from a water supply port and filled therein. An ultrasonic oscillator that irradiates ultrasonic waves for inducing cavitation to water inside the water guide tube, a degassing chamber depressurized by a vacuum pump, and pump means for sending water in the water guide tube to the degassing chamber. Water supply means for supplying water stored in the degassing chamber to the outside, and the pump means generates a rising rotational vortex of an axial center substantially along the axial direction of the water guide tube in the water inside the water guide tube. The pump is characterized in that the pump comprises a centrifugal pump that absorbs water from a region near the axis of the upper end of the water guide tube and discharges and scatters discharged water into the degassing chamber.

Preferably, the centrifugal pump comprises a vertical shaft type radial flow or mixed flow turbine pump or a volute pump having a lateral discharge port for directly discharging discharge water from an outer peripheral portion of the impeller into the deaeration chamber. Is substantially directly coaxially connected to the upper end of the water guide tube, and the discharge port is directly opened into the degassing chamber.

It is preferable that the degassing chamber has an abutment wall for receiving water discharged from the volute pump and scattering the water.

Further, a circulation system for circulating at least a part of the water from the water supply means to the water pipe may be further provided.

In the degassing apparatus of the present invention, the water in the water guide tube is induced to decompress at low temperature and boil due to ultrasonic waves in the degassing chamber, and the dissolved gas in the water is mixed with the water by the vortex pump. The air is led to the degassing chamber as air bubbles, and the air is collected and suctioned from the degassing chamber to its decompression source to degas, so that the decompression for degassing can be used for introducing water, and the heating energy for boiling the treated water. Is unnecessary.

By the way, when the water temperature in the water pipe is low as in winter, the viscosity of the water increases, and the bubbles and water generated in the low-temperature water have a strong viscous force. Although it tends to be difficult, in the deaerator of the present invention, the water introduced into the water pipe from the water supply pipe by irradiating ultrasonic vibration energy to induce cavitation in the water in the water pipe. Is provided with an ultrasonic transducer for generating cavitation.

Therefore, even if the degree of the pressure reduction is smaller than the case where the water causes boiling under reduced pressure only by the vacuum pressure, the cavitation phenomenon by the ultrasonic vibration energy induces a cavitation phenomenon in the water, and the dissolved gas in the water is introduced into the cavity. It is trapped as bubbles, which are collected at the axis of the upward rotating vortex by the vortex pump, are sucked by the vortex pump, and are discharged into the degassing chamber under reduced pressure, and are released as gas to the degassing chamber. Therefore, deaeration can be effectively performed from a vacuum pump connected to the deaeration chamber as a reduced pressure source. of course,
It is effective to use ultrasonic irradiation in combination even when the pressure in the degassing chamber is reduced to a sufficiently low pressure and the water in the water guide tube itself boils under reduced pressure.

In general, cavitation by ultrasonic waves
Occurs when sound pressure exceeds atmospheric pressure. Therefore, if the sound pressure of the ultrasonic wave is (p), the density of the water to be treated is (ρ), the vibration speed of the particles is (u), and the propagation speed of the wave is (c), p
= Ρcu. Further, the intensity of the sound wave, that is, the power density (I) is I = ρcu ² .

Since the density of water to be treated is greatly affected by the content of impurities such as volatile components and organic substances in the water, in the present invention, a plurality of ultrasonic vibrators are preferably mounted on the bottom surface of the water pipe, and The ultrasonic intensity is controlled by controlling the number of operating elements and the voltage and current of the driving power supply, and cavitation is generated in the water column in the water pipe before the degree of vacuum reaches the saturated water vapor pressure of the water in the degassing chamber. The gas is efficiently bubbled, and the bubbles are drawn into the upward rotating vortex by the vortex pump and converge on the axis of the gas, and are discharged from the upper end of the water guide tube in the radial direction into the degassing chamber. The fine bubbles contained are removed by vacuum degassing in a degassing chamber.Thus, such degassing forms degassed water with extremely weak oxidizing power and then, for example, into an ion exchange resin cylinder. By Komu Ri, it is possible to effectively prevent deterioration of the ion exchange resin.

The improvement of the degassing effect by the ultrasonic vibration is remarkable, and unlike the conventional ultrasonic vibration method in which the water surface in a general water receiving tank is open to the atmosphere, the present invention employs a water pipe. Since the degassing chamber communicating with the upper part of the inside is performed under reduced pressure conditions, the gas corresponding to the equilibrium partial pressure does not dissolve again in the degassed water from the atmosphere, and the chlorine odor It is possible to obtain high-purity degassed water which is not nearly pure water.

Particularly preferably, the dimensions of the water guide tube and the frequency of the ultrasonic vibration are selected so that the standing wave of the ultrasonic vibration is given to the water filled in the water guide tube from the bottom of the water guide tube in the upright state. As a result, a standing wave of ultrasonic waves is formed in the water column filling the water pipe, and the maximum ultrasonic vibration energy is transmitted because the ultrasonic waves are completely reflected on the water surface, thereby instantaneously generating cavitation and dissolving The gas vigorously becomes bubbles and ruptures on the water surface, and is collected and removed from the depressurized upper degassing space in the water pipe, thereby further improving the degassing efficiency.

In this case, the shape of the water guide cylinder is a frusto-conical cylinder whose inner diameter gradually decreases as it goes upward from the lower part in order to collect air bubbles generated in the cylinder at the axial center and to quickly raise the suction. Preferably, a volute pump is directly connected to the top. Various types can be used as the centrifugal pump. Preferably, the centrifugal pump radiates water discharged from the outer periphery of the impeller directly into the degassing chamber without a vortex chamber or a fixed or movable guide blade. Using a vertical radial flow type or vertical mixed flow type turbine pump or volute pump having a discharge port, this pump is directly connected substantially coaxially to the upper end of the water pipe, and the discharge port is also preferably provided over the entire circumference. It is composed of a plurality of slit-shaped openings arranged at various intervals, which are directly opened into the degassing chamber, so that water containing air bubbles is sprayed into the degassing chamber from the entire circumference of the pump in a mist state. Good.

The impeller (rotor) of the vertical shaft type centrifugal pump is a single-sided open rotor with one end face closed, and a horizontal discharge port formed of a plurality of slit-like openings is formed around the entire circumference to act on the water flow. When provided in a direction perpendicular to the direction of the centrifugal force, it is difficult for the groove vortex of the opposite direction to oppose the centrifugal force to be formed between the blades of the pump rotor and the blades, thereby causing bubbles accompanying the water flow to be generated by the blades and the blades. The advantage is that there is no stagnation during this time, and the pumping efficiency of the pump itself is not reduced. Of course, it goes without saying that the angle and shape of the rotor blades can be optimally designed according to the use conditions.

The deaeration chamber in which the water guide tube is disposed is depressurized from the atmospheric pressure by a vacuum pump, and water is sucked into the water feed port from the water supply port to fill the water guide tube with water. When the rotor is rotated, a water flow is discharged from the pump into the deaeration chamber while a rotating upward vortex is generated in the water guide tube due to the vacuum pressure in the deaeration chamber and suction by the pump rotor, and water is absorbed into the water guide tube and enters the deaeration chamber. Is continuously performed. At this time, bubbles are actively generated in water in the water guide tube due to cavitation by ultrasonic waves applied to the water guide tube at the same time as boiling under reduced pressure, and the bubbles are caught in the rotating ascending vortex. In this case, since the air bubbles have a specific gravity lower than that of water, most of the air bubbles collect at the axis of the upward rotating vortex, and are sucked into the pump together with the vortex from the axis of the pump rotor.

The sucked water and air bubbles are separated from each other by centrifugal force acting on the water flow driven by the rotation of the rotor, and form a mist from a plurality of slit-shaped discharge ports on the entire circumference to escape laterally. The air is injected into the air chamber, and the air bubbles are sucked and collected by the vacuum pressure in the deaeration chamber to perform the deaeration. The degassed water is temporarily stored in the lower part of the degassing chamber, and is taken out from the lower part of the degassing chamber to the outside as needed by an external pump. During this time, the water level in the degassing chamber may be monitored, and the water supply system and the drainage system may be controlled by the operation of the solenoid valve and the pump so that a constant water level is always maintained.

It is preferable to provide an abutting member for radiant water in the degassing chamber so as to face the discharge port of the volute pump, and the wall of the degassing chamber itself can be used as the abutting member. When the atomized water containing bubbles ejected from the discharge port collides with the abutment member, the colliding bubbles are forcibly destroyed along with the water, thereby releasing the gas in the bubbles to the degassing chamber. Therefore, the trapping of gas by depressurization becomes effective, and the degassing effect is further enhanced. The gas separated by the rupture of air bubbles is collected and sucked from the degassing chamber by a decompression source such as a vacuum pump, while the degassed water is naturally dropped and stored in the lower part of the degassing chamber. A guide gutter or the like for sedation may be arranged in the degassing chamber so as to be gently introduced into the lower water storage surface.

Furthermore, it is preferable that a closed loop circulation system is formed by connecting the water reservoir below the degassing chamber and the water supply port of the water pipe by an external piping system including, for example, an on-off valve and a water pump. In this case, the suction amount Q of the centrifugal pump is set equal to the sum of the supply amount Q1 of fresh water to the water supply port per unit time and the circulation flow rate Q2 of circulating water flowing through the circulation system per unit time (ie, , Q = Q1 + Q2), fresh water supply Q
If the apparatus is operated under conditions such that the ratio m (where m = Q2 / Q1) of 1 to the circulation flow rate Q2 is greater than 1, water accumulated in the degassing chamber can be repeatedly degassed. In addition, it becomes possible to obtain highly degassed water in which the residual dissolved gas is completely eliminated.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a preferred embodiment of the present invention, in which a main unit is a degassing chamber 7 whose inside is depressurized by a vacuum pump 17, and is vertically inserted into the degassing chamber. A water pipe 15 is provided, a plurality of ultrasonic vibrators 12 attached to the bottom of the water pipe, and a vertical shaft pump 3 installed at the top of the water pipe. The water introduced into the water guide tube 15 via the ejector 13 and the manual opening / closing valve 26 is ejected from the lateral discharge port 4 to the deaeration chamber 7 by the volute pump 3 and is sent to the deaeration chamber 7. Water is supplied to the outside by the water supply pump 10, and a part of the water is returned from the distribution casing 22 to the water supply system by the ejector 13 via the manual opening / closing valve 27 to form a circulation system.

The water pipe 15 is a generally frusto-conical shape having a lower water supply port 25 at a position above the bottom surface thereof.
Then, the inside is filled with water introduced through the valve 26, and the water filling the inside is given a reduced-pressure low-temperature boiling and cavitation phenomenon. A plurality of ultrasonic transducers 12 for irradiating ultrasonic waves to water in the water guide cylinder to induce a cavitation phenomenon are arranged at the bottom of the water guide cylinder 15, and each vibrator is driven by a power box 19. Have been.

The centrifugal pump 3 has a rotor (impeller) 1 which rotates in a rotor casing 2 directly attached to the top of a water guide tube 15, and the upper surface of the rotor 1 is closed by a closing disk 20. It is composed of a radially arranged impeller of an open bottom type, and is driven to rotate by a motor 6 around an axis coaxial with the water guide tube 15. On the peripheral wall of the casing 2, there are provided horizontal discharge ports 4 each having a plurality of slit-shaped openings at equal intervals, and a mist-like water flow discharged from the discharge ports 4 is directly radiated into the deaeration chamber 7, and the deaeration chamber is formed. The mist-like discharge water stream is brought into contact with the inner peripheral wall of the nozzle.

The centrifugal pump 3 of the present embodiment generates an upward rotating vortex of an axial center substantially along the axial direction of the water guide tube with respect to the water inside the water guide tube 15 from the region near the shaft center at the upper end of the water guide tube. Although it is a vertical-shaft turbine pump that absorbs water and radiates water discharged from the outer periphery of the impeller directly from the discharge port 4 into the deaeration chamber 7, a volute pump may be used as long as the same function is performed.

The apparatus is operated in a vacuum pump 1
The inside of the degassing chamber 7 is maintained in a high vacuum state by 7, and the exhaust from the vacuum pump 17 is diffused into the atmosphere. When the electromagnetic valve 18 is opened in this state, water sent from a water receiving tank (not shown) via the water supply pipe 9 is sucked from the water supply port 25 via the injector 13 and the valve 26 into the water guide cylinder 15 under a reduced pressure state. . When the ultrasonic wave at a predetermined frequency is applied to the water in the water guide tube from the ultrasonic oscillator 12 arranged at the bottom of the water guide tube 15 in a state where the water guide tube 15 is filled with water, Cavitation is induced in the water by cavitation, and the gas dissolved in the water is separated as bubbles 14. The low-temperature boiling phenomenon under reduced pressure also contributes to this bubble generation.

At this time, when the centrifugal pump 3 is operated by the motor 6, the rotation of the rotor 1 causes
An upward rotating vortex of the axial center along the axial direction of the water guide cylinder is generated in the water inside, and this vortex is sucked together with the air bubbles from near the axial center of the rotor 1 while entraining the air bubbles and collecting them at the axial center, thereby closing the rotor. The gas flows radially along the disk 20 and is degassed as a high-speed jet laterally from the plurality of slit-shaped discharge ports 4 of the peripheral wall of the casing 2 by centrifugal force without causing air bubbles to stay between the blades of the rotor 1. Radiated into the chamber 7.

In this case, the high-speed jet flow is cut at the edge of the slit when passing through the slit-shaped discharge port 4, and is scattered and radiated to the degassing chamber as a mist-like jet flow.
This further abuts against the inner wall of the degassing chamber, whereby fine bubbles remaining in the water droplets are also separated by themselves. Therefore, the released water is sucked and collected by the vacuum pump 17 and exhausted out of the apparatus. Is done.

As described above, the volute pump 3 in the present embodiment sucks water containing bubbles and discharges the bubbles as a mist-like high-speed jet without stagnating in the pump.
This is one of the features that cannot be realized by a conventional general pump.

The water thus degassed is temporarily stored in the lower water storage chamber 21 in the high vacuum state degassing chamber 7.
The water storage chamber 21 has water level detectors a, at three height levels.
b and c are provided, and the water level is monitored and controlled by the external control device 16. That is, the detector a is for detecting the stop water level of the water pump 10, and the detector b is for detecting the water pump 1
0 for detecting the starting water level, and detector c is a solenoid valve 1
8 for detecting the closed water level.

The control device 16 determines whether the level of the degassed water is
If the water level exceeds, the water supply pump 10 is activated,
Thereby, the pump 10 is connected from the water storage chamber 21 through the pipe 11.
Degassed water is sent to the outside and the circulation system. When the water level in the water storage chamber 21 falls below the water level of the detector a, the water pump 10 is stopped by the control device 16 until the water level recovers to the water level of the detector b, and the water level in the water storage chamber 21 is further detected. When the water level of the vessel c is exceeded, the solenoid valve is closed by the control device 16 and the supply of fresh water is stopped.

When the degassed water is sent from the water pump 10 in this manner, a part of the water sent to the outside by the distribution casing 22 is sent to the circulation pipe 23 through the valve 27,
The water is supplied to the water supply port 25 of the water guide tube 15 via the water supply intake injector 13 and the valve 26. Ejector 13
In this case, the feed water from the solenoid valve 18 is sucked and taken in by the negative pressure generated when the circulating water (deaerated water) from the circulation pipe 23 passes at high speed, and the negative pressure due to the reduced pressure in the apparatus and the water pump 1
Water is sucked into the water guide tube 15 by a pressure based on the sum of the zero pushing pressure.

[0043]

As described above, the deaerator according to the present invention synergizes with the effects of high vacuum and ultrasonic cavitation by utilizing the effect of the centrifugal force of the vortex generated by the vortex pump in an atomizing and jet-combining manner. Degassing, it is possible to effectively degas not only dissolved oxygen in the water but also volatile gas components.Turn the tap water into highly degassed water with almost no oxidative corrosion Not only contributes to the corrosion protection and prolonging of life, but also can detoxify carcinogenic organic volatile components such as benzene in the wastewater resulting from crude oil refining, for example. There is also no way to open the way to collect degassed benzene and use it as a raw material for insecticides, etc. Also, since there is no clogging point in the equipment, it can also be used to remove carcinogens of chlorine derivatives from factory wastewater River water It is intended to also effective to prevent pollution.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a preferred embodiment of the present invention as a longitudinal sectional structure.

[Explanation of symbols]

 3: Volute pump 7: Deaeration chamber 10: Water pump 15: Water pipe 17: Vacuum pump

Claims (4)

[Claims] 1. A water pipe for introducing water from a water supply port and filling the inside thereof with a reduced pressure low-temperature boiling and hollowing phenomenon, and an ultrasonic wave for irradiating the water inside the water pipe with ultrasonic waves for inducing a hollowing phenomenon. A sonic vibrator, a deaeration chamber depressurized by a vacuum pump, a pump means for sending water in the water guide tube to the deaeration chamber, and a water supply means for sending water stored in the deaeration chamber to the outside. The degassing device, wherein the pump means absorbs water from a region near the axis at the upper end of the water guide cylinder while generating a rising rotational vortex of the axis substantially along the axial direction of the water guide cylinder in the water inside the water guide cylinder. A degassing device comprising a vortex pump that discharges and discharges water into the degassing chamber. 2. The vertical pump according to claim 1, wherein the centrifugal pump comprises a vertical shaft-type turbine pump or a volute pump having a horizontal discharge port for directly radiating discharge water from an outer periphery of an impeller into a deaeration chamber.
The deaerator according to claim 1, wherein the pump is directly coaxially connected to an upper end of the water guide tube, and the discharge port is directly opened into the deaeration chamber. 3. The degassing device according to claim 1, wherein the degassing chamber has an abutment wall for receiving water from the volute pump and scattering the water. 4. The deaerator according to claim 1, further comprising a circulation system for circulating at least a part of the water from the water supply means to the water pipe.